Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 03 2024 23:26:36 AWUS01 KWNH 032326 FFGMPD NVZ000-CAZ000-ORZ000-040525- Mesoscale Precipitation Discussion 0796 NWS Weather Prediction Center College Park MD 725 PM EDT Sat Aug 03 2024 Areas affected...Northwest NV...Northeast CA...Central and Southern OR Concerning...Heavy rainfall...Flash flooding possible Valid 032325Z - 040525Z SUMMARY...Some additional increase in the coverage of locally heavy showers and thunderstorms can be expected over the next few hours across areas of northeast CA, northwest NV and into central/southern OR. This will drive a threat for isolated areas of flash flooding going through this evening which will include potential burn scar impacts. DISCUSSION...The late afternoon GOES-W visible satellite imagery shows an increasingly agitated and expansive CU/TCU field across northeast CA, northwest NV and up to areas of south-central to southeast OR. Scattered areas of showers and thunderstorms have already initiated, with some of the stronger cells seen currently over far northern Washoe County in northwest NV. The convection across the region is being strongly influenced by the presence of an elongated but well-defined mid-level circulation/vort center over the central and northern Sierra Nevada with energy from this extending well north over areas of central and southern OR. Mid-level forcing associated with this energy coupled with diurnal heating/surface-based instability and orographics has been leading to the development and gradual expansion of convection over the last 1 to 2 hours, and with the latest satellite and radar trends, an additional expansion of at least scattered to locally broken areas of heavy showers and thunderstorms can be expected. The PWs across the region are quite anomalous, especially over central and southern OR where they are near the 99th percentile of climatology and over 3 standard deviations above normal. These high PWs are confirmed in the latest CIRA-ALPW plots with a fairly strong concentration of monsoonal moisture seen in the 700/500 mb and 500/300 mb layers. The moisture environment coupled with the uptick in late-day instability should set the stage for areas of efficient convection that will be capable of producing 1.5 to 2 inch/hour rainfall rates. Relatively slow cell-motions and a threat locally for some of the convection to become focused near areas of high terrain may support some spotty rainfall totals of 2 to 4 inches going through the evening hours. These rains will foster at least an isolated threat for flash flooding, and some of these concerns will involve multiple burn scar locations where impacts may be significant. This includes active fire areas in particular across portions of central and eastern OR. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9gxihXeVespsyNF0RabLETkDR8kl7pXPEq1u7tKNd99k0s6RmJBBWCQxo7xNDvGhsHDx= Hpp0OvJsDszHGzELDuwytAA$ for graphic product... ATTN...WFO...BOI...LKN...MFR...PDT...PQR...REV... ATTN...RFC...CNRFC...NWRFC...NWC... LAT...LON 44752018 44391853 43791761 42681716 42001758=20 41601872 40871976 40822074 41812207 43022254=20 44232218 44642133=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .